use lazy_static::lazy_static; // 1.3.0

use std::sync::atomic::{Ordering, AtomicBool};

static VERBOSE: AtomicBool = AtomicBool::new(false);

fn log_or_not(value: &str) {
    if VERBOSE.load(Ordering::SeqCst) {
        println!("{}", value);
    }
}

fn main() {
    log_or_not("foo");

    VERBOSE.store(true, Ordering::SeqCst);

    log_or_not("bar");
}